MOSCOW, July 21. /TASS/. Russia’s work on designing and developing the Sarmat heavy intercontinental ballistic missile (ICBM) is at the third stage and tests will start in 18-24 months, Aide to the Strategic Missile Force Commander Igor Denisov said on Tuesday.

"As of today, the third stage of the design and development work is under way. I believe we’ll reach the stage of tests of this heavy missile in 18-24 months," he said.

The Sarmat heavy ICBM is designed to replace the Voyevoda (NATO reporting name: SS-18 Satan) ICBM operational in the Russian Strategic Missile Force, the aide said.